The United States went to war in Afghanistan in 2001, Iraq in 2003, and Syria—sometime after 2011, depending on how we define “war” in this era of ill-defined and boundless U.S. engagement in hostilities the world over.

In the early days, American involvement in Syria’s chaos was mostly remote. As Syrian President Bashar al-Assad’s brutal suppression of civilian protests devolved into civil war, then-President Obama called for regime change, closed the U.S. embassy in Damascus, drew a red line around chemical weapon use, and unsuccessfully petitioned Congress for authority to attack. Since then, the rise and fall of the Islamic State has seen a gradual expansion of American presence on the ground in Syria, beginning with airstrikes plus arms and training for comparatively moderate militants and escalating from there.

Today, there may be as many as 4,000 U.S. boots on the ground in Syria. Airstrikes continue, and though they have slowed since last year’s peak, the Trump administration has now twice bombed regime targets. And while ISIS is all but vanquished, Syria’s civil war grows all the more complex. U.S. forces now find themselves dodging (with varying degrees of success) conflict with Russian and Iranian troops backing Assad while Turkish soldiers—our NATO allies—are fighting U.S.-backed Kurds. President Trump says he wants to bring American soldiers home, but his administration has spuriously boasted of authority to keep them in Syria indefinitely.